daylight bulbs

Having shot a roll of film on my kids over Xmas, portrait style, I'm not happy. I've got a TTL flashgun but unfortunately the extension lead is not too long so it limits my work. Looking at lightboxes I think this might be the way to go for me. I like the odea of being able to see the immediate effect of the light I'm applying. i'm pretty good at joinery and the electrics is not a problem so i could make my own. However, in the interim, has anyone ever used the daylight lamps? Theyr'e pretty cheap and some sort of inline diffusion can be rigges up allowing for the heat generated, but what about the colour cast? Anyone used these before?

Without a colour temperature meter it becomes fiddly but not impossible to find out the temperature of your lights - providing you have a reasonable digital camera.
Get a large piece of matt white card and light it.
Take a series of pictures of the card with the same exposure, each time changing the colour temperature setting manually.
If the lights are cooler than the temp you have set the card will look yellowish.
If the lights are hotter then the card will look bluish.
When the card looks white then you have found the colour temperature.
Note: this only works properly if you have calibrated your monitor.

(But if you save your images in RAW you can play with the colour temp later)

Then you'll have to do a test roll - or borrow someone's digital. If you have access to a new-ish video camera, they have colour temp settings.
For the test roll you will need to use the white card and if you can get hold of some CC filters, that would help.